MUSCULAR SYSTEM

Medical Science I

MUSCULAR SYSTEM Over 650 muscles Nearly half our body weight comes

from muscles Consist of muscles and connective

tissueMuscles give us form and shape.Muscles produce most of our body

heat.

TYPES OF MUSCLES Skeletal muscle Smooth muscle Cardiac muscle Sphincter muscle

SKELETAL MUSCLES muscles attached to bones striped or striated because of bandings Voluntary muscles Multinucleated muscle cell bundles = muscle

fibers SARCOLEMMA = cell membrane Contract quickly, fatigue easily, can’t maintain

contraction for long period of time

SMOOTH MUSCLE Found in walls of digestive system,

uterus and blood vessels Visceral muscle Only one nucleus No striations Involuntary controlled by autonomic

nervous system

CARDIAC MUSCLE Involuntary heart muscle Striated and branched Involuntary Cells are fused – when one contracts,

they all contract

SPHINCTER MUSCLE Special circular muscles Open and close to control passage of

substances in openings of esophagus, stomach,

small intestine, anus, urethra and mouth

TYPES OF CONNECTIVE TISSUE Tendons Fascia

TENDONS Connect skeletal muscle to bone

FASCIA Fibrous connective tissue sheets that wrap

around muscle bundles

MUSCLE CHARACTERISTICS

ContractibilityElasticityExcitabilityExtensibilityTone

CONTRACTILITY when a muscle shortens and reduces

the distance between two parts

ELASTICITY- ability to return to the original length

when relaxed

EXCITABILITY ability to respond to stimuli

EXTENSIBILITY ability to be stretched

MUSCLE TONE Is a stat e of being slightly contracted

and ready to pull Isotonic- muscle contracts and

shortens ex. Walk Isometric- tension increase but doesn’t

shorten ex. Crunches Atrophy- muscle may shrink or waste

away from lack of use Hypertrophy- enlargement of the

muscle cell

MUSCLE FATIGUE Is caused by a build up of lactic acid in

muscles which impedes contraction Oxygen converts lactic acid back to

glucose after exercise oxygen debt- amount of oxygen

needed after exercise to return lactic acid back to glucose

HOW MUSCLES ARE NAMED Location of muscle Size Number of origins Location of origin Action Not all muscles are named this way

MUSCLES OF FACIAL EXPRESSION Frontalis- raises eyebrows & wrinkles

forehead Orbicularis oris- open and close lips Orbicularis oculi- closes eyelid Zygomatic major- raises corners of mouth

(smiling) Buccinator- cheek muscles

MUSCLES OF MASTICATION

Massester- closes jaw

Temporalis- Raises jaw, closes mouth and moves jaw backward

Sternocleidomastoid- flexes head, rotates head

MUSCLES OF THE NECK

HEAD AND NECK MUSCLES

TORSO/TRUNK MUSCLES (ANTERIOR)

MUSCLES OF THE TRUNK/TORSO External intercostals- raise ribs helps

w/ breathing Diaphragm- helps control breathing Rectus abdominis-compresses

abdomen External and internal obliques-

decompress ribs, flexes spinal column and abdominal cavity

Latissimuss dorsi- extension, adduction, flexion from standing and internal rotation of the shoulder

TORSO/TRUNK MUSCLES (POSTERIOR)

MUSCLES OF UPPER EXTREMITY Trapezius-moves shoulders, extends head Deltoid-abduct the upper arm Pectoralis major- flex upper arm, helps

abduct upper arm Biceps brachii- flexes lower arm Triceps brachii-extends lower arm Brachioradialis- pronation/supanation,

flex at elbow

UPPER EXTREMITY MUSCLES

MUSCLES OF THE LOWER EXTREMITY Gluteus Medius-abducts and rotates

thigh Gluteus Maximus-extends femur and

rotates outward Vastus lateralis- extends knee Vastus medalis- stabilizes patella Gastrocnemius-points toe and flexes

lower leg

MUSCLES OF THE LOWER EXTREMITY Soleus- extends foot Sartorius- flexes and rotates thigh and

leg Tibialis anterior- dorsiflex foot, walking

on heel Rectus femoris- flexes thigh & extends

lower leg

MUSCLES OF THE LOWER EXTREMITY Hamstrings- a group of four muscles

on the BACK of the thigh Quadriceps- group of four muscles on

the FRONT of the thigh

LOWER EXTREMITY MUSCLES

FUNCTIONS OF THE MUSCULAR SYSTEM Movement Posture Body heat

MOVEMENT Skeletal muscle-origins and insertions

help muscles move origins- part of skeletal muscle attached to fixed

structure Insertions- attached to moveable part

MOVEMENT Smooth muscle- causes movement of

the digestive system Cardiac muscle causes movement of the

heart Acetycholine- chemical neurotransmitter Motor unit-motor neuron plus all the

muscle fibers it stimulates Neuromuscular junction- junction

between the motor neuron fibers which transmits the impulse, and the muscle cell's sarcolemma

POSTURE How does the muscular system help

with posture?

BODY HEAT Muscles release ATP for energy When ATP is released it produces heat

and energy

DISORDERS OF THE MUSCULAR SYSTEM Fibromyalgia Hernia Muscle spasms Muscular dystrophy Myasthenia gravis Strain Tendonitis Tetanus

FIBROMYALGIA A collection of symptoms

Chronic muscle pain 3 or more month Fatigue Headache Numbness and tingling Joint pain

Treatment is pain relief, enough sleep, exercise, massage, chiropractor, and stretching

HERNIA When an organ protrudes through a

weakened muscle 3 types

Abdominal Inguinnal Hiatal

http://www.youtube.com/watch?v=R6pwlIVQPVA

MUSCLE SPASMS Also called muscle cramp Sustained contraction of the muscle,

which may be due to overuse

MUSCULAR DYSTROPHY Muscle cells deteriorate Most common type is Duchenne’s

which is a birth defect Symptoms

Muscle weakness that progresses Falls Delayed walking

No treatment managing symptoms only

MYASTHENIA GRAVIS Autoimmune disorder- immune system

attacks healthy tissue Symptoms-

Voluntary muscle weakness Difficulty swallowing or chewing Paralysis

Treatment Plenty of rest Avoid stress and heat Medications There is no cure

http://www.youtube.com/watch?v=mt0efT2xk2Y

STRAIN A tear in the muscle resulting from

excessive use Treatment=RICE

Rest Ice Compression Elevation

TENDONITIS Inflammation of the tendons Symptoms

Joint stiffness Heat Redness Swelling

Treatment RICE medication

TETANUS Also called lockjaw Caused by toxin entering through puncture

wound Symptoms

Spasms of voluntary muscles that start in jaw and move throughout body

Treatment Antibiotics Rest

Tetanus vaccine to prevent http://

www.youtube.com/watch?v=AX5K_uvhL6w http://

www.youtube.com/watch?v=lCZxffNcFxw